Awesome! Fedora also, and this is a step towards countering "Trusting Trust" toolchain issues

Posted Feb 3, 2015 22:29 UTC (Tue) by nix (subscriber, #2304)
In reply to: Awesome! Fedora also, and this is a step towards countering "Trusting Trust" toolchain issues by nix
Parent article: Lots of progress for Debian's reproducible builds

Of course this is wrong. Profile-guided optimizations *that depend on nondeterministic test runs* are out of the question. If the test run is deterministic (thus the branches taken are unchanging across multiple runs), then of course profile-guided optimizations are not incompatible with reproducible builds.

Awesome! Fedora also, and this is a step towards countering "Trusting Trust" toolchain issues

Posted Feb 4, 2015 8:55 UTC (Wed) by cesarb (subscriber, #6266) [Link] (1 responses)

Does profile-guided optimization add profiling code to all branches, or does it use a timer (and a signal) to sample the basic blocks? If it uses a timer, it won't be deterministic.

Awesome! Fedora also, and this is a step towards countering "Trusting Trust" toolchain issues

Posted Feb 17, 2015 19:42 UTC (Tue) by nix (subscriber, #2304) [Link]

It instruments arcs between basic blocks, so it's deterministic.